Parkinson's disease is a progressive neurodegenerative disease with a primary symptom of extrapyramidal function abnormality. Pathologically, loss of dopaminergic neurons and alpha-synuclein deposition in the substantia nigra pars compacta are observed. Clinically, various motor symptoms such as akinesia, tremor, rigidity, and loss of postural reflexes are exhibited.
Parkinson's disease therapy is fundamentally a drug therapy intended to supplement intracerebral dopamine. A drug comprising levodopa (L-dopa), which is a dopamine precursor, is used as the first-line drug for the initial therapy of Parkinson's disease. However, motor complications such as Parkinson's Disease Levodopa induced dyskinesia (hereinafter, also referred to as “PD-LID”) are manifested in almost all patients undergoing levodopa therapy with the progression in pathological conditions.
The frequency of developing PD-LID in 5 years after the initial levodopa therapy is 30 to 50%. The frequency increases with the progression of the pathological condition and reaches 50 to 100% in 10 years after the initial therapy. Peak-dose dyskinesia is known as an exemplary symptom of PD-LID, which is an involuntary movement manifested in the face, tongue, neck, limbs, body trunk, or the like when the blood levodopa concentration is high.
Patent Literature 1 [Japanese Laid-Open Publication No. 11-228414] has a disclosure on transdermally absorbed tandospirone agents.